Cellulose ester composition



Patented July 26, 1932 UNITED STATES PATENT OFFICE GEORGE ROCKER, OF WES'IFIELD, AND EDMUND B. IIDDLETON, OF NEW BRUNSWICK, NEW JERSEY, ASSIGNORS TO DU FONT VISCOLOID COMPANY, INC or WILIING'ION; DELAWARE, A CORPORATION OF DELAWARE OELLULOSE ESTER COMPOSITION No Drawing.

This application is a continuation in part of our co-pending application S. N. 138,565 filed September 29, 1926.

This invention relates to cellulose ester compositions suitable'for use in the plastic and analogous arts, such as sheet or film manufacture and the production of coating com positions.

One object of our invention is to reduce a composition which is highly elastic in its finished and dry state. Another object is to produce a composition which may be made into strong and highly elastic sheets or films capable of retaining elongation and of remaining' free from brittleness for a great length of time. It is a further object to produce a composition capable of easy manipulation in the plastic film and coating composition arts. Another object of the invention is to provide a composition containing a volatile solvent in which the rate of volatilization of the solvent is reduced and blushing is prevented in the finished film or coating.

These and otherobjects are attained by providing a cellulose ester composition containlng a softener comprising an ether of glycerol, particularly t e methyl ether of glycerol.

Illustrative of a specific embodiment of our invention the following examples are given as representing highly satisfactory film dope compositions (proportions being given in parts by weight) Example] 10 parts nitrocellulose 1 part camphor 1 part mono-methyl ether of glycerol 15 parts methyl alcohol parts acetone I Ewampla Application filed 0mm 8, 19:11.v sum in. men. J

to have satisfactory solvent properties with regard to cellulose acetate.

Example 3 10 parts nitrocellulose l part methyl ether of glycerol 1 part camphor 15 parts methyl alcohol 25 parts acetone 1 part zinctacetate 73 parts nitrocellulose Example 5 15 parts camphor 7 10 parts mono-methyl ether of glycerol 1 part urea I 1 part zinc acetate 50 parts gypsum 5O rts titanium oxide 73 parts nitrocellulose The following exam les are illustrative of compositions suitable or use as lacquers and enamels Example 6 30 parts toluol 5 parts alcohol 10 parts butyl alcohol 20 parts butyl acetate v 5 parts dimethyl ether of glycerol 10 parts ethyl acetate 10 parts ester gum 10 parts low viscosity cellulose nitrate E'aaample 7 08 36 parts toluol 5 parts alcohol 10 parts-butyl acetate 10 parts ethyl acetate 5 parts dimethylether of glycerol no Example 7-Continued a parts plasticizer 7 parts ester gum 8 parts low viscosity cellulose nitrate 15 parts pigments It is understood that the examples given are merely illustrative as the proportions of the various ingredients may be varied wide- 1y, depending upon the properties desired and the use to which the composition is to be put. In general, it has been found that the glycerol ether softener may be varied from about 1 to based on the Wei ht of cellulose ester employed. Any suita le solvents, such as aromatic phosphates (e. g. tricresyl phosphate) in place of the camphor, etc., may be used in making up the desired composition. Additional softeners, fire-proofing agents, igments, etc. may also be added.

The g ycerol ethers which are used in the compositions forming the present invention lliave the following general structural formua ore-on H-OR Ha-OR in which It represents hydrogen or methyl groups. These compounds are excellent softeners for the cellulose esters, particularly cellulose acetate, whereas it has been found that the ethyl ether of glycerol is not a satisfactory solvent for cellulose acetate. In general the ethers of glycerol are practically non-volatile colorless, practically odorless and many 0t them are somewhat hygroscopic.

Films, lacquer coatings and plastics made from compositions containing the glycerol ether softeners are highly elastic and retain their elongation. The finished roducts remain free from brittleness for ong eriods of time and films containing the g ycerol ether softeners are characterized by their increased pllasticity as compared with the usual type of 1m. When used in coating compositions such as lac uers, the softeners decrease the rate of volati ization of the lacquer solvent and thereby aid in preventing blushing of the finished coating. The lycerol ether softeners are further characterized by being hi hly stable.

he cellulose ester compositions containing the' glycerol ether softeners are adapted to a great variety of uses such as for lacguers, enamels, sheets or films, pyralin and or other cellulose ester plastics. The use of such compositions results in products having highl desirable properties and being ca able of wide application.

ilms or sheets may be produced by the use of our compositions in any of the usual methods familiar to those skilled in the art, such as by flowing or casting the compositions on suitable casting surfaces (e. g. glass) aeeaeei and allowing the contained volatile solvents to evaporate.

Other desirable changes in composition, use and methods of preparation may be made Without departing from the spirit and scope of the invention.

We claim:

1. A composition of matter comprising a cellulose ester and a methyl ether of glycerol.

2. A composition of matter comprising cellulose acetate and a methyl ether of glycerol.

3. A composition of matter comprisin celluloie acetate and mono-methyl ether 0 glycero 4. A flexible clear film 'formed by flowing or casting and subsequently drying a solution comprising approximately 5 parts of cellulose acetate dissolved in approximately 20 parts of acetone and approximately 1 part of a methyl ether of glycerol.

In testimony whereof we afiix our signatures.

GEORGE ROCKER. EDMUND B. MIDDLETON. 

